Polycarbonates are polymers that may be derived from bisphenols and phosgene, or their derivatives. They are useful for forming a wide variety of products, such as by molding, extrusion, and thermoforming processes. Such products include articles and components that include auto parts, electronic appliances, and cell phone components. Because of their broad use, particularly in electronic applications and auto part applications, the desired properties of polycarbonates include high impact strength and toughness, heat resistance, weather and ozone resistance, and good ductility.
However, polycarbonate polymers are not inherently non-flammable. It is thus typically necessary to include flame retardant additives, such as halogenated or non-halogenated additives, that retard the flammability of the and/or reduce dripping. Halogenated flame retardants containing bromide and/or chloride are increasingly subject to regulatory restrictions. Non-halogenated alternatives, including various fillers, phosphorous-containing compounds, and certain salts, have been used. However, it has been difficult to meet strict flame retardance standards using these non-halogenated alternatives, particularly in thin wall samples, while maintaining the desired properties of impact strength and ductility.
Accordingly, there exists a need for improved polycarbonate compositions that exhibit good heat resistance, while maintaining physical and mechanical properties suitable for the intended application.